To provide continuous service for a user, a mobile terminal has to carry out a handover process to change from one access channel to another. This change of channel may also cause the change of base station or another network element, such as a network element controlling a base station or core network element, for example a mobile switching centre or a support node of packet-switched services. It should be noted that handover may even occur to another kind of system (inter-system handover), for example between the GSM network and 3GPP (Third Generation Partnership Project) UMTS network (Universal Mobile Telecommunications System) and/or WLAN (Wireless Local Area Network).
Handover often occurs because the signal quality of the channel currently providing the transmission service is not good enough. Typically, a mobile terminal is arranged to measure the signals of the currently serving cell and the surrounding cells at specific time intervals. The quality of the currently used signal is compared with estimates of other available signals, and based on criteria set by a handover algorithm, a decision is made on whether to change the channel. Typically, at least signal strength is used by the handover algorithm. Other criteria are error rates, transmission power levels, traffic volume and naturally the total loss of the current connection. If the outcome of the handover algorithm is that the channel will be changed, signalling is initiated between the mobile terminal and the access network(s).
Today, many mobile terminals are capable of providing a wide variety of telecommunications services. For instance, a terminal may be capable of providing circuit-switched speech and data transfer services, packet-switched data transfer services and messaging services such as SMS (Short Message Service). These services may be provided via one type of network or different types of networks. For instance, the packet-switched data transfer service of the terminal may be provided by a connection to a wireless. local area network access point and the circuit-switched services may be provided by a connection to a public land mobile network (PLMN). In current networking applications, the application stays connected using the connection settings that were initially selected when the connection was established. Thus, handovers are only made within the currently serving system. Even if a new type of connection becomes available, the application will typically continue to use the original connection settings. WO 99/25146 discloses a dual-mode mobile phone wherein the user may, by pressing a specific button, initiate handover between a fixed network and a mobile network. When the dual-mode phone is leaving the fixed network coverage area, the phone sends a signal strength warning tone to the user. The user may then press the “handover” button, thereby causing the initiation of call transfer to the mobile network. However, it may be that the user is not actively using his terminal, for instance the device may be in the user's pocket, and the indication does not reach the user. In this kind of situations, the handover algorithm execution and the related measurements and comparisons prior to the indication may unnecessarily waste the terminal's resources as the user is not interested in changing from one network to another.